Bracket pulsar[notes 1] is a period-3 oscillator discovered by Hartmut Holzwart on the 5th of March, 1993. Despite being identical in population and bounding box to the pulsar, it is much rarer, having never appeared naturally so far. However, one in 21,000 odd-width eightfold symmetric soups (D8_1) form a bracket pulsar in the centre.
It is one of three notable extensible families of p3 oscillators with D8 symmetry, the others being the pulsar and the cross. Its next extension is the bracket quasar, named in analogy to the quasar.
Unlike the pulsar and cross families, the quadrants of the bracket pulsar are able to be skewed in relation to each other. For the pulsar case this permits three derivative oscillators, one with a single 2-cell shift, and two with an additional 2-cell shift:
- 48P3.12 at Heinrich Koenig's Game of Life Object Catalogs